Multiple description coding (MDC) is a coding technique which encodes a video sequence into n independent sub streams (n>=2), referred to as descriptions. The packets of each description are routed over multiple, and sometimes partially disjoint, paths. In order to decode the media stream, any description can be used; however, the quality improves with the number of descriptions received in parallel.
MDC techniques provide error resilience to media streams. Since an arbitrary subset of descriptions can be used to decode the original stream, network congestion or packet loss, which is common in networks such as the Internet, will not interrupt the stream but only cause a temporary loss of quality. The quality of a stream can be expected to be roughly proportional to the data rate sustained by the receiver.